Enamel firing stand



Feb. 21, 1956 A. H. EDGERTON 2,735,921

ENAMEL FIRING STAND Filed May 4, 1954 INVENTOR. ARTHUR E'DGf/YTON TOENEYS:

United States Patent ENAMEL FIRING STAND Arthur H. Edgerton, Rocky River, Ohio Application May 4, 1954, Serial No. 427,521

Claims. (Cl. 219-19) This invention relates broadly to apparatus for firing vitreous enamel on jewelry and light industrial articles and more specifically to improvements in the structure of the work holder and arrangement of the heating element relative thereto.

Heretofore it has been the practice to fire enamel coated articles in a mufile furnace or kiln which embodied, generally, a heating element, a control unit therefor, and a housing having a door or aperture therein for access to the chamber defined by the housing. In such kilns the Work was placed in the heating chamber and inspected from time to time until the appearance of the work indicated complete fusion of the enamel.

Frequently maturity of the enamel or so-called glaze could not be detected without removal of the work from the kiln which obviously eifectuated a thermal change in the firing chamber of the kiln and altered the firing rate of the enamel. In some equipment the enamel coated articles were placed directly on an electric heating element, the progress of fusion being observed by the shade of incandescence of the Work and/or Withdrawal of the heated article from the kiln. In either case the results were uncertain since enamels of different grade and density mature at various temperatures, which effect the appearance or shade of incandescence of the Work. Moreover, removal of the work from the firing chamber lowers the temperature of the kiln and arrests fusion of the enamel until the thermal condition of the work is restored.

In the present invention the foregoing dilficulties are eliminated by supporting the work with the enamelcoated surface thereof subjacent the heating element so that fusion of the enamel may be effected by radiation. Such organization of the heater affords the ready inspection of the work without alteration of the firing rate.

One of the objects of the invention is to provide an enamel firing stand which is formed with a work holder mounted below the exposed open coil in a heating element so that fusion of an enamel coated article placed on the holder may be effected by radiation.

Another object of the invention is to provide a holder which is designed for vertical adjustment relative to the heating element in order to accommodate the support of articles of various depth or thickness.

Another object of the invention is to provide a work holder which is adapted for pivotal movement, eccentric the heating element, to facilitate inspection of the progress of fusion of an enamel coated article on the holder.

Further objects of the invention reside in the provision of a firing stand which is efiicient of operation, economic of manufacture, safe in use, and designed to facilitate inspection of the Work during the firing cycle with ease and dispatch.

Other objects and advantages more or less ancillary to the forgeoing, and the manner in which all the various objects are realized, will appear in the following description, which considered in connection with the accompanying drawings, sets forth the preferred embodiment of the invention.

Referring to the drawings:

Fig. 1 is a plan view of the improved firing stand.

Fig. 2 is a side elevational view thereof, portions of the holder being broken away and shown in section; and

Fig. 3 is a side elevational view of a modified form of the firing stand and work holder.

Referring first to Fig. 2 the firing stand comprises an electric heating element 10 supported on a sheet metal channel bar 11 having an elongated flange 12 on the base thereof which is provided with a threaded post or stantion 13 constituting a support for a work-holding plate 14. The plate is formed with a clearance hole 15 in the center thereof for free pivotal movement upon the post 13 and a sleeve 16 is affixed upon the upper face thereof to restrain depression of the inner free end of the holder when the work is placed thereon. The plate 14 is supported by a nut 17 tapped for snug engagement with the threads on the post 13 in order to resist rotational movement thereof when the plate is revolved for inspection of the work during the firing operation. The nut is provided to facilitate vertical adjustment of the plate to accommodate work pieces of variable thickness or depth.

The flange 12 is preferably provided with a heat insulating pad 18 such as asbestos or a ceramic material, though legs or stantions may be used, if desired, in lieu thereof.

The heating element 10 may be of any conventional form which embodies a ceramic base having a spiral groove therein for the reception of a helical coil of resistance wire coupled with terminals 19 fashioned to receive the socket on an electric cord of usual form. The heater is mounted with the open or exposed heating coil facing downwardly so the heat therefrom may be focused on the subjacent work piece to melt the enamel coating thereon by radiation.

In operation, the nut 17 is adjusted to support the plate so that the work piece resting thereon will clear the coil about one sixteenth to one eighth of an inch. The electric current is then turned on and after a few minutes the plate 14 may be revolved about its fulcrum to bring the work into view. If fusion of the enamel has not matured, the plate may be returned to bring the work under the coil and the firing operation continued. This operation may be repeated until the glaze becomes fiuidic, at which time the electric current may be turned off, the plate revolved to draw the end thereof from beneath the coil and the work removed or permitted to cool.

In the modified form illustrated in Fig. 3 a second heating element 20, electrically connected to the coil 10 by buss bars 21, is mounted on the flange 12 in opposition to the heater 10, but with the exposed coil facing upwardly. As illustrated, the plate 14 is formed with an upturned flange 22 on the end thereof for the support of a wire frame 23 constituting the work holder or so-called trivet. The trivet comprises two pairs of arms 24 disposed at right angles to each other, each converging inwardly and downwardly to a common point so the peripheral edge of a work piece may be supported on the inclinatory edges thereof. In this embodiment as in the former case, the enamel is subjected to the radiant heat generated by the electric coils.

The frame or trivet 23 may be employed with the firing stand of the form illustrated in Fig. 2 if desired, provided the work piece is of a size or shape that will accommodate the support thereof in contiguous relation to the coil.

Although the foregoing description is necessarily of a detailed character, in order that the invention may be completely set forth, it is to be understood that the specific terminology is not intended to be restrictive or confining, and that various rearrangements of parts and modifications of detail may be resorted to Without departing from the scope or spirit of the invention as herein claimed.

1. Apparatus for firing vitreous enamel on metal ar' ticles comprising a stand embodying a base, a vertical leg thereon, a horizontal flange on the upper portion of said leg parallel said base, an electric heater formed'to produce temperatures within a range of 1300Y-F to 1600 F. on said flange disposed intconfronting relation with said base, a threaded post on said base mounted beyond-the edge of said heater, a nut on said post and awork supporting plate pivotally mounted on said post and'su'pported by said nut whereby metal articles coated with vitreous enamel that fuses at approximately 1500 F. may be placed on said plate elevated by said nut into close proximity with said heater, rotated in a horizontal plane under the heating element to effect the fusion of the vitreous enamel and momentarily rotated from beneath the heating element to inspect the progress of fusion of the vitreous enamel and accommodate the removal thereof upon maturity of fusion. I

2. Apparatus for firing vitreous enamels on metal articles comprising a channel bar, having confronting horizontal flanges, an electric heater formed to produce temperatures from 1300 to 1600 F. mounted on the inner face of the upper flange of said channel bar, a threaded post on the lower flange thereof remote from said heater, a nut on said post, a plate supported for verticle adjustment pivoted on said post, said plate being disposed in subjacent relation with said heater for supporting metal articles coated with a vitreous enamel that fuses at a temperature of approximately 1500 F.

3. Apparatus for firing vitreous enamel on metal articles comprising a stand, an electric heater which produces a temperature of at least 1500 F. mounted in a horizontal position on said stand with the heating element facing downwardly, a work holder subjacent the heating element in said heater, a jack screw remote from said heater for adjusting said holder vertically toward and away from said heating element, a sleeve secured to said plate and freely rotatable on said jack screw, whereby metal articles coated with a powdered vitreous enamel a 4 a that melts at 1500 F. may be rotated under said heating element and fused.

4. Apparatus for firing vitreous enamels on metal articles comprising a channel bar having horizontal confronting flanges, an electric heater producing 1300 to 1600 F. mounted on the inner face of upper flange of said channel bar, a threaded post on the lower flange of the channel, a nut on said post, a plate pivoted on said post and supportedby said nut below said heating element whereby work pieces of various thicknesses which are coated with vitreous enamels that melt at a temperature of 1500 F. may be elevated into proximity with said heating element and rotatively retracted therefrom when the enamel has melted.

5. Apparatus for firing vitreous enamels on metal articles comprising a channel bar, having confronting horizontal flanges, an electric heater formed to produce temperatures from 1300F. to 1600"; F. mounted on the inner face of the upper flange of said channel bar, a second similar heating element mounted on the inner face of the lower flange of said channel bar, a threaded post on said lower flange remote from said heaters, a nut on said post, a work holder supported for vertical adjustment pivoted on said post, said work holder being disposed intermediate said heating elements for supporting metal articles coated with a vitreous enamel that fuses at a temperature of approximately 1500 F.

References ited in the file of this patent Carron Nov. 9, 1954 

1. APPARATUS FOR FIRING VITREOUS ENAMEL ON METAL ARTICLES COMPRISING A STAND EMBODYING A BASE, A VERTICAL LEG THEREON, A HORIZONTAL FLANGE ON THE UPPER PORTION OF SAID LEG PARALLEL SAID BASE, AN ELECTRIC HEATER FORMED TO PRODUCE TEMPERATURES WITHIN A RANGE OF 1300*F. TO 1600* F. ON SAID FLANGE DISPOSED IN CONFRONTING RELATION WITH SAID BASE, A THREADED POST ON SAID BASE MOUNTED BEYOND THE EDGE OF SAID HEATER, A NUT ON SAID POST AND A WORK SUPPORTING PLATE PIVOTALLY MOUNTED ON SAID POST AND SUPPORTED BY SAID NUT WHEREBY METAL ARTICLES COATED WITH VITREOUS ENAMEL THAT FUSES AT APPROXIMATELY 1500*F. MAY BE PLACED ON SAID PLATE ELEVATED BY SAID NUT INTO PROXIMITY WITH SAID HEATER, ROTATED IN A HORIZONTAL PLANE UNDER THE HEATING ELEMENT TO EFFECT THE FUSION OF THE VITREOUS ENAMEL AND MOMENTARILY ROTATED FROM BENEATH THE HEATING ELEMENT TO INSPECT THE PROGRESS OF FUSION OF THE VITREOUS ENAMEL AND ACCOMMODATE THE REMOVAL THEREOF UPON MATURITY OF FUSION. 